Projector

Abstract

There is provided a projector comprising, a light source unit having a laser light emitter and a projection light producing device for converting the laser light into projection light, a display unit and a light guiding optical system which forms a projection optical path along which light from the light source unit is guided to the display device, the projector comprising a partial light separation unit which reflects or transmits part of light emitted from the projection light converting device of the light source unit so as to separate the part of the light to an optical path which is different from the projection optical path, a photosensor which is disposed on the optical path which is separated and changed by the partial light separation unit, a light intensity determination unit which detects an light intensity of the laser light which is separated by the partial light separation unit so as to determine whether or not the light intensity exceeds a threshold, and a light source control unit which stops the emission of the laser light emitter based on the result of the determination of the light intensity determination unit.

What is claimed is: 
     
       1. A projector comprising:
 a light source unit having a laser light emitter for emitting laser light and a projection light producing device for converting the laser light into projection light; 
 a display unit; 
 a light guiding optical system which forms a projection optical path along which light from the light source unit is guided to the display device; 
 a partial light separation unit which is disposed in a predetermined position on the projection optical path and which reflects or transmits part of light emitted from the projection light producing device of the light source unit so as to separate the part of the light to an optical path which is different from the projection optical path; 
 a photosensor which is disposed on the optical path which is separated and changed by the partial light separation unit; 
 a light intensity determination unit which detects a light intensity of the laser light which is separated by the partial light separation unit so as to determine whether or not the light intensity exceeds a threshold; and 
 a light source control unit which stops the emission of the laser light emitter based on a result of the determination of the light intensity determination unit; 
 wherein the partial light separation unit separates and changes an optical path for part of light shone on to a mirror which reflects or transmits light emitted from the projection light producing device of the light source unit by providing a light transmitting portion or a reflection angle changing portion in a spot area of the laser light on the mirror. 
 
     
     
       2. The projector as set forth in  claim 1 , wherein when the result of the determination of the light intensity determination unit exceeds the threshold, the light source control unit stops the emission of the laser light emitter. 
     
     
       3. A projector comprising:
 a light source unit haying a laser light emitter for emitting laser light and a projection light producing device for converting the laser light into projection light; 
 a display unit; 
 a light guiding optical system which forms a projection optical path along which light from the light source unit is guided to the display device; 
 a partial light separation unit which is disposed in a predetermined position on the projection optical path and which reflects or transmits part of light emitted from the projection light producing device of the light source unit so as to separate the part of the light to an optical path which is different from the projection optical path; 
 a photosensor which is disposed on the optical path which is separated and changed by the partial light separation unit; 
 a light intensity determination unit which detects a light intensity of the laser light which is separated by the partial light separation unit so as to determine whether or not the light intensity exceeds a threshold; and 
 a light source control unit which stops the emission of the laser light emitter based on a result of the determination of the light intensity determination unit; 
 wherein the partial light separation unit separates and changes an optical path for part of light shone on to a mirror which reflects or transmits light emitted from the projection light producing device of the light source unit by providing a light transmitting portion or a reflection angle changing portion in any other position other than a spot area of the laser light on the mirror. 
 
     
     
       4. The projector as set forth in  claim 3 , wherein when the result of the determination by the light intensity determination unit is less than the threshold, the light source control unit stops the emission of the laser light emitter. 
     
     
       5. The projector as set forth in  claim 1 , wherein the photosensor comprises a CCD sensor or a CMOS sensor. 
     
     
       6. The projector as set forth in  claim 4 , wherein the photosensor comprises a photodiode.